Question: Give the chemical compound with the least speed of sound who is part hydrogen?
Paraphrase: What is the hydrogen chemical compund with the least speed of sound?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q11173 . ?ent wdt:P2075 ?obj . ?ent wdt:P527 wd:Q556. } ORDER BY ASC(?obj)LIMIT 5 
Answer: hydrogen iodide, hydrogen bromide, hydrogen sulfide, hydrogen chloride, Ammonia